College of Pharmacy, Faculty of Health Professions, Dalhousie University, Halifax, Nova Scotia, Canada.
Pharmacotherapy. 2010 Mar;30(3):254-64. doi: 10.1592/phco.30.3.254.
Clinical studies have suggested a possible association of low serum vitamin D levels in patients with bone fractures. This, coupled with a high prevalence of fractures and increases in associated disability and mortality, begs the question, is there evidence to support a role for therapeutic drug monitoring of vitamin D levels to prevent bone fractures? We use a previously published nine-step decision-making algorithm to answer this question. Optimal dosages of vitamin D have not been determined, although daily intake guidelines are suggested. Current vitamin D assays yield varying results, making it challenging for clinicians to interpret results from clinical trials and apply them directly to patients and their specific serum level data. Fracture risk is not easily assessable clinically, with no clear relationship between vitamin D concentrations and bone mineral density. The existing primary literature shows no clear relationship between vitamin D concentrations and fracture risk; target concentrations are not well established. Although the pharmacokinetic parameters of vitamin D are unpredictable and vitamin D supplementation is frequently lifelong, results of a vitamin D assay are unlikely to make a significant difference in the clinical decision-making process (i.e., provide more information than clinical judgment alone). Most published studies on vitamin D levels and fracture risk did not control for other potential reasons to monitor levels, multifactorial risks for fractures, and other confounders. Given limited data to support a direct relation between vitamin D levels and clinical outcome of fracture, inconsistent between-assay results, and no consensus on optimal levels, there is insufficient evidence to recommend routine therapeutic drug monitoring of vitamin D for fracture prevention; however, other reasons for monitoring might exist that are beyond the scope of this review. Recent availability of vitamin D assay standards may lead to future improvements in comparability of research data, establishment of a target range, and interpretability of patient results.
临床研究表明，血清维生素 D 水平低的患者与骨折有关。再加上骨折的高发率以及相关残疾和死亡率的增加，不禁让人质疑，是否有证据支持通过监测维生素 D 水平来治疗药物以预防骨折？我们使用之前发表的九步决策算法来回答这个问题。虽然建议了每日摄入量指南，但尚未确定最佳维生素 D 剂量。目前的维生素 D 检测方法得出的结果各不相同，这使得临床医生难以解释临床试验结果并将其直接应用于患者及其特定的血清水平数据。骨折风险在临床上不易评估，维生素 D 浓度与骨矿物质密度之间没有明确的关系。现有主要文献表明，维生素 D 浓度与骨折风险之间没有明确的关系；目标浓度尚未确定。尽管维生素 D 的药代动力学参数不可预测，而且维生素 D 补充通常是终身的，但维生素 D 检测结果不太可能在临床决策过程中产生重大影响（即，提供的信息比临床判断本身更多）。大多数关于维生素 D 水平与骨折风险的已发表研究都没有控制其他可能的监测原因，如骨折的多因素风险和其他混杂因素。鉴于支持维生素 D 水平与骨折临床结果之间直接关系的有限数据、检测结果不一致以及对最佳水平没有共识，没有足够的证据推荐常规监测维生素 D 以预防骨折；但是，可能存在超出本综述范围的其他监测原因。最近维生素 D 检测标准的可用性可能会导致未来提高研究数据的可比性、建立目标范围以及解释患者结果的能力。
